data loss with ssh -n

[Pekka Savola]

Hi,

Using OpenSSH 2.9p2 (2.5.2 was also bad), I've noticed data loss on
Linux when:
 1) ssh -n flag is used, and
 2) ssh jobs are run from cron (effectively causing the same as above).

What is done, is a command basically like:

ssh [-n] -c blowfish -p 722 -i rsakey -l pwget passwdserver passwd > passwd.tmp 2> /tmp/log

ie, retrieve dynamically created passwd-file from passwdserver using rsa
keys.

The server is SSH 1.2.25 or the like (yeah, I know it's broken, but can't
be changed at the moment).

The diff of ssh -v -v -v is:

--- log	Fri Jul 20 13:18:42 2001
+++ log.cron	Fri Jul 20 13:02:01 2001
@@ -41,13 +41,12 @@
 debug3: clear hostkey 0
 debug3: clear hostkey 1
 debug3: clear hostkey 2
-debug1: Requesting X11 forwarding with authentication spoofing.
-debug1: Remote: X11 forwarding disabled in server configuration file.
-Warning: Remote host denied X11 forwarding.
 debug1: Sending command: passwd
 debug1: Entering interactive session.
+debug1: fd 0 setting O_NONBLOCK
 debug1: fd 1 setting O_NONBLOCK
 debug1: fd 2 setting O_NONBLOCK
-debug1: Transferred: stdin 0, stdout 155303, stderr 0 bytes in 1.6 seconds
-debug1: Bytes per second: stdin 0.0, stdout 95576.3, stderr 0.0
+debug1: Sending eof.
+debug1: Transferred: stdin 0, stdout 155303, stderr 0 bytes in 1.5 seconds
+debug1: Bytes per second: stdin 0.0, stdout 100654.4, stderr 0.0
 debug1: Exit status 0

When run from cron, or with -n, you get "Sending eof." which truncates the
data.

Any ideas?

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords